The Arctic Ocean could be free of summer sea ice as soon as sometime in this decade, and it’s extremely likely by 2050, according to a new study by the National Oceanic and Atmospheric Administration (NOAA). That’s much sooner than the previously projected time frame of after mid century.
Not only has the timetable for a summer ice-free Arctic been reset, it seems there is a subtle shift in message from the NOAA: we should no longer be debating what will happen if the sea ice melts; it’s now more about the consequences of when it does.
Since the NOAA researchers used three different methods to make this newest prediction, however, some are saying it proves that even scientists believe that climate change models can’t be completely trusted.
So, is attention intentionally being deflected away from what inevitably is going to happen to our planet to the process used to predict it?
A three-pronged approach
In the study, the NOAA researchers themselves admitted that “there is no one perfect way to predict summer sea-ice loss in the Arctic.” So they utilized three different methods. All three resulted in widely different dates, but overall, they still suggested nearly sea-ice-free summers in the Arctic before the middle of this century.
In the first of the three approaches, named the “trendsetters,” the scientists used observed sea-ice trends. Over the past decade, trends have showed that total Arctic sea ice decreased rapidly. By projecting these trends into the future, a nearly sea-ice-free Arctic would appear to be the case by the year 2020.
The second approach, called the “stochasters” approach, was based on assuming future multiple—but random in time—large sea-ice-loss events such as those that occurred in 2007 and 2012. Using this method, it is estimated that it would take several more such events to reach a nearly sea-ice-free state in the summer. Factoring in the likelihood of such events, results suggest a nearly sea-ice-free Arctic by about 2030, although there is a large uncertainty in the timing.
In the third approach, or “modelers,” the large collection of global climate change model results was used to predict atmosphere, land, ocean and sea-ice conditions over time. These models showed that the earliest possible loss of sea ice will be around 2040, as greenhouse gas concentrations increase and the Arctic warms. The median timing in these models is closer to 2060, although the researchers noted that there are several reasons to believe that this median timing of sea-ice loss may be too slow.
In summary, then, extending summertime sea-ice melting trends into the future predicts an ice-free Arctic by 2020. Adding a few random up-and-down events to current melting trends pushes the date back to 2030, while a more complicated climate change model suggests an ice-free Arctic in 2040—possibly 2060. But none of these methods foresees the polar ice cap remaining intact long-term.
The devil is in the details
When all three approaches are considered, it seems clear that the Arctic will certainly be nearly ice-free in summer within the next 10 to 45 years. The researchers emphasize that the word nearly is important, since some ice is likely to remain on the northern edges of the Canadian Arctic Archipelago and Greenland.
That quantification and the widely disparate dates resulting from the three methods have caused some to interpret the report as showing that no sort of modeling is useful. Due to the inherent unpredictability of climate systems, they say, it is impossible to accurately use models to determine future weather. Since climate models have been unable to simulate major known features of past epochs, such as the Ice Ages or the very warm climates of the Miocene, Eocene and Cretaceous Periods, they should not be trusted to predict future climate changes. Even Jonathan Gilligan, associate professor of earth and environmental sciences at Vanderbilt University, has written that models “can’t predict the exact details with a lot of confidence.”
Other contrarians point to the recent news of record sea ice recovery. However, it is important to point out that such a result should be expected since the minimum extent of the ice is declining faster than the maximum extent.
Still, all in all, say the NOAA researchers, the study shows that Arctic sea-ice loss is very likely to occur in the first rather than the second half of the 21st century, with a possibility of loss within a decade or two.
Do you think that the negative reactions to the methodology details and varying dates of such studies is just a means to deflect attention away from the bigger conclusion that Arctic summer sea ice will soon disappear? Or is it just “good science” to question the process of prediction?
Here’s to finding your true places and natural habitats,